BRUSSELS, June 8 - Russia has threatened to cut off gas supplies to Ukraine for political reasons, immediately after announcing the completion of a new pipeline to Germany, EUObserver reported Monday.

Russian President Vladimir Putin did it at the St Petersburg International Economic Forum on Friday, which was attended by Austrian chancellor Sebastian Kurz and former German chancellor Gerhard Schröder.

Putin said the first link in the Germany pipeline, called Nord Stream 2, was finished and that Russian state firm Gazprom was ready to fill it with gas.

"Gazprom's ready for deliveries, but everything will depend on the German regulator," he said.

When the St Petersburg forum's moderator mentioned that Russian gas currently "feeds" Ukraine's transit pipelines to the EU, Putin interjected, saying: "Do you think we should feed everyone? Do we have such a duty to feed everyone, or what?".

He said he would honor existing contracts for Ukraine transit supplies, worth some EUR 2 billion a year to Kyiv.

But speaking of supplies in the long term, he added: "Everything's possible, we're ready for this and we want it [future Ukraine transit], but we need goodwill on the part of our Ukrainian partners".

"Spend money not in order to maintain the army and aim it at solving the problems of Donbas by force, but in order to improve the economy, work with people - do you understand?," Putin said.

Donbas is a region in east Ukraine which Russia invaded in 2014 after a pro-Western revolution in Kyiv.

Moscow wants Kyiv to give two Russia-puppet 'republics' in the occupied zone a constitutional status in a federalized Ukraine.

The threat of politically motivated gas-cut offs, which could also hit Poland and the Baltic states, was the main reason why they and the US had opposed Nord Stream 2.

But German chancellor Angela Merkel has backed it for the sake of cheaper and more secure gas for German people.

Her predecessor, Schröder, now works for Gazprom.

And Kurz, who spoke at the St Petersburg event by video-link, also praised Nord Stream 2.

"Austrian companies are taking part in this. We, as well as Germany and some other European countries, see it in a positive way," he said.

"Nord Stream 2 now provides us with safe, modern gas pipeline routes ... we're very optimistic about it," Kurz said. (euo/ez)